that's the nice thing about them big diesels.
as long as it has clean fuel and hot battery.. it likely 'started' up fine after setting for years.
again.. the roof and doors would be a total non issue to me.
the setting for years would only be an issue IF it had running problems. If it has been run a few months since setting and has no other problems.. I'd call it ok. Sounds like it has a new clutch.. that's a bonus.
the 3pt stuff missing. that's not an issue per-se.. but rather an expense. I'd try to find a set of gear off a salvage tractor of similar size vs buying new... AND verify that the 3pt worked. if the 3pt didn't work.. now that would be an issue..e tc.
as for the cab....10 minutes with some 7/16 osb board and a saw and you can cut a top to fit, then caulk it in after fitting it with angle iron tabs if needed, then paint it, or put some of that roll rubber matting on the top if you don't care how it looks.. or go nice and lay some fiberglass up there and then sand / blend in to the FOPS, and then paint.
doors? if it has AC i gues I'd build / find doors for it. if it ain't got ac.. I'd forget about the doors unless you were dusty-plowing all day long in which case I'd again.. make some doors out of 7/16 osb, cut windoes and use plexiglass panels for the windows, and then paint the doors up blue, and make whatever latch and hinge hardware needed to close the doors... add weather stripping.. etc. again.. with a bit of work, it wouldn't look redneck.. using that tough liner style rubber paint will seal the wood good and get rid of the wood grain.. or you could use fiberglass on the wood doors too.. or find a junkyard set.
as far as size on your land? about 82 engine hp and 72 pto hp?

sounds good to me.
I have about 20 tractors

one of them is a 7610s at about 95 engine hp, next biggest is a 5000 at about 70 eng hp.. etc. then the bulk of the rest are in the high 40's hp range with a few in the 34hp range and a few in the 10hp range..
i got 13.2 ac...

using my math..and you have 17 ac.. I'd say you could use a 110hp tractor and be fine..

.. plus have a few extra helper machines.
the 4wd is just icing on the cake.
soundguy
Missing all the 3 point gear,missing the doors and roof.
As to maintenance,well...seller said it sat outside for 6 years with a bad clutch before he bought it three years ago.
Do you think it is too big for the size of our property?